Textile material containing organic esters of cellulose and method of preparing same



Patented eb. 22,

UNITED amen TEXTILE MATERIAL CON'EMNIING URGANTIE ESTERS OF CELLULOSIE AND METHOD 03F PREPARING SAME tion of Delaware No Drawing. application April 3,

Serial No. 114,472

12 Claims.

This invention relates to the preparation and manufacture of yarns, filaments, fabrics and other articles from organic esters of cellulose, which organic esters have been subjected at least 5 in part to the action of a saponifying agent and relates more particularly to the preparation of the yarns and filaments of organic esters of cellulose prior to the application thereto of a basic material for the purpose of saponifying same or sensitizing same for subsequent saponiflcation.

An object of the invention is the economic and expeditious production of textile materials containing yarns and filaments of an organic esters of cellulose, at least a part of said materials having been treated with a saponifying agent. A further object of this invention is the partial and intermittent saponification of yarns during a winding operation and the preparation of such yarns, so that they will evenly and quick- 1y react to the saponifying material and/or permit the saponifying material to quickly penetrate into the filaments immediately upon contact therewith and to an extent sufiicient to use up substantially all the saponifyingmaterial or at least carry it into the filaments prior to being wound upon the take-up package so that blurring or streaky saponification is prevented. Other objects of the invention will appear from the followingdetailed description.

I have found that the speed with which a saponii'ying agent reacts with or is caused to penetrate into a yarn containing organic esters of cellulose is proportionate to the amount of moisture contained in the filaments of the yarn 35.and;;also that the depth and evenness of the saponifying action is proportionate to the amount of moisture contained in the filaments of the yarn. By-employing this invention, which, in

; general, consists in conditioning the yarn prior to 40 treatment=with a saponifyi-ng agent such that it contains substantially its maximum content of moisture. regain, there may employed less l saponifying material, which reduction in saponifyingrnateria-l [also produces a reduction in the 4 Namount ofecryst'als of salt formed on the yarn.

By'thus reducingwthe amount of crystals atthe -11acessaponified the yarn becomes more amenable to textile operations. By employing this in- "fntion-yaims maybe sufficiently saponified durng thewilnding operation so that they become nsitiaedior further and heavy saponification in wi tho'utproducing on the yarn a suffic nt ,amQui tjofg-crystalline material tointer- 'ie1e"'withthe "same as the yarns are passed which results in an even saponification.

through guides, needles, etc., in the future processing operations.

By employing this invention the sapo-nification of the yarns during the winding operation is caused to go to completion very rapidly. In this manner when periodically or intermittently saponifying yarns there is developed a very sharp line between the part saponified and the untreated part as the action of saponification and the penetration of the saponifying agent is so rapid that the tendency of the saponifying medium to travel along the yarn is prevented as the same is used up prior to any substantial lengthwise movement thereof.

By employing this invention there may be prevented any action of the saponifying agent upon the uncontacted area of the yarn. In prior methods of intermittently or periodically saponifying yarns during a winding operation the action of the saponifying agent was not carried sufliciently toward completion prior to winding of the yarn upon the take-up package, thus producing an action on the uncontacted part of the yarn where the contacted part of the -yarn crossed same in the package. Although the action of the saponifying agent after it had reached the takeup package was slight, in future treatments and development of the yarn by treatment in a soap bath these places receiving slight actions were amplified to such an extent that in a dyed material a smudge or blur was produced. By employing this invention very strong concentrations of saponifying agents may be placed on the yarn during the winding operation, yet the same is sufficiently reacted or carried to the interior of the filaments so that there is substantially no transfer of unreacted saponifying agents from the treated portion of the yarn to the untreated portion of the yarn on the take-up package. This gives rise to clear cut lines between the treated and the untreated part of the yarn.

By employing this invention a still further ad- 'vantage is obtained in that the saponified yarn produced is more evenly saponified.

- of a furnishing device during a winding operation, it is very diflicult to contact all parts of the yarn with an even amount of saponifying material. However, by employing this invention the evenness of application is compensated for by the afilnity of the yarn for the saponifying agent though any unevenness in saponification is slight during this operation if the material is later treated in a soap solution and then dyed any unevenness is greatly magnified and becomes very obvious. By employing this invention fabrics may be further developed by treatment in soap baths and the like and then dyed which do not show an unevenness of saponification.

In accordance with my invention then I partially and lightly saponiiy yarns and filaments containing organic esters of cellulose, which yarns contain substantially a maximum amount of moisture regain to sensitize the same, which sensitizing may cover the entire yarn or filament or may be applied thereto intermittently, periodically or at random, and then either before or after forming the yarns and filaments into fabrics I treat the same in a bath having a pH value from 8 to 11 or more for the purpose of developing or further saponifying the yarn or only that part of the yarn which has been sensitized. Also, in. accordance with my invention, I treat yarns and filaments or textile materials such as warps or fabric containing organic esters of cellulose by placing same in a humid atmosphere having a fairly high relative humidity so that the yarns, etc. will regain a substantial amount of moisture and then treat these yarns with a basic material, for instance, with the aid of a printing device, for the purpose of saponifying them or sensitizing the same for saponification.

This invention is applicable to the treatment of yarns or filaments or fabrics of any suitable ester of cellulose that is capable of being partially and/or totally saponifled by treatment with bases. For example, I may employ this invention in the treatment of yarns and filaments and fabrics formed from the nitrates of cellulose or the organic esters of cellulose or mixture of same. Examples of organic esters of cellulose are cellulose acetate, cellulose propionate and cellulose butyrate. The yarns or filaments containing these materials may be formed by either the wet or dry method of spinning and may contain besides the derivatives of cellulose, dyes, lakes, fillers, plasticizers and lubricants.

Yarns and filaments or textile materials formed of the esters of cellulose may contain up to 5.5% or more, on their weight, of moisture depending upon the humidity of the atmosphere in which they are placed. These materials regain a moisture content corresponding to the rise in relative humidity of the atmosphere in which they are placed. For instance, cellulose acetate which has been stored for a period of time may drop in moisture content such that the moisture content is below 1 per cent. However, when placed in an atmosphere containing a relative humidity of 65% or above, the yarns and filaments will regain a moisture content of up to 5.5 or more of their weight. The speed of action and penetration of any saponifying agent ap:

plied to the yarns will be proportionate to the amount of moisture that the yarn has regained prior to contact with the saponifying agent even though the saponifying agent be applied to the yarns from an aqueous solution. Thus, for producing sharp lines of saponiflcation and an even saponifying action, it is preferable to have this moisture regain or content of the yarn as near the maximum as possible.

For the purpose of producing substantially the maximum moisture regain in the yarn or fabric prior to contacting same with a saponifying agent, the yarn may be stored immediately prior to contacting with the saponifying agent in a chamber or container, the atmosphere of which is kept fairly saturated with moisture, that is, for instance, an atmosphere having a relative huniidity of above 40 per cent. Further, the yarn may be made more susceptible to the action of the saponifying agent at the winding operation by placing the feed bobbin on the winding machine in a humidor having a fairly high humidity, for instance, about 85 per cent relative humidity. A still further method of building up the moisture regain of the yarn is to surround the twisting machine, or at least that part of it traversed by the yarn, by an atmosphere that has a relatively high humidity, for instance, about 65 per cent relative humidity. The maintaining of the atmosphere, through which the yarn passes during the winding operation, at a high percentage of relative humidity is of advantage even when the yarn has been previously conditioned or when it is fed from a humidor. The atmosphere may be kept at a high humidity by the escaping of steam near the feed of the yarn or by suitabl humidifiers employing atomized Water, place near the machine. Any other suitable method r device may be employed for supplying the yarn with sufiicient moisture that the moisture regain or moisture absorbed by the yarn is approximately that of the maximum moisture content that the yarn will pick up.

This invention is particularly applicable to the treatment of yarns or fabrics with a saponiiying agent during a winding operation, for instance, by contacting the yarns with a furnishing device supplying thereto a solution of a basic material capable of producing at least sufiicient saponifi cation to etch the surface or the yarn. Thus, after the yarns have been conditioned, by raising their moisture content, and made susceptible to the saponifying action they may be caused to pass over a wick or. roller that clips into a solution containing a base material. The yarns may be caused to contact the wick or roller continuously or periodically to produce yarns which are lightly saponified or sensitized throughout their length or only at certain periods of their length. For fabrics this can be done on any suitable device, for instance, on a printing machine. When treating fabrics the fabric may be conditioned by storage in a moist atmosphere and/or unrolled from a suitable humidor.

The saponifying agent applied to the yarns or fabrics during the winding operation need only be sufiicient to etch the yarns as the heavy or substantial part of the saponification can be later developed by treating the yarns or fabrics in a soap solution or other bath having a relatively mild saponifying action, or one that would not normally saponify the material at all. The developing bath produces a saponificaticn of the material at the parts sensitized during the winding operation and has substantially no efiect upon that part of the yarn or fabric not contacted with the saponifying material during the winding operation. The action of applying a saponiiying agent to the material during a winding operation such that there is a. partial saponiflcation of the yarn or fabric to an extent that the loss in weight of the yarn at those pointscontacted is from 2 to 7 per cent of their weight may be termed a sensitizing action.

The sensitizing material may be any suitable basic material or a solution of a base material having a pH value of from 10 to 14. Any suitable basic solution may be employed for this purposesuch as. an aqueous solution or an alcoholic solution of an alkali hydroxide, for inacids, organic compoun amass? ti agents may be employed. By varying the stance, sodium hydroxide or potassium hydroig ide, an aqueous solution of a nmon m hydroxide, a salt of a strong has" alkali and a weak acid action, etc. Examples of m and an organic acid which be employed as the sensitizin mary, secondary and tertia stance, ethanol amine, methanol anol amine, di-ethanol amine} amine and tri-ethanol amine. Als' nary ammonium bases may be' m loye stance, tetramethyl ammonium ethyl ammonium hydroxide, etc.

These materials may be applie 7 from aqueous solutions which solutionsinay be of any suitable concentration such as the pH value of the solution has a value of above -1 In the treatment of yarns which are "t'cr'be' used n certain types of machines wherein they etneces: sity must pass through small guide eye's and needles, it is some times advisable to select a sensitizing agent which, when applied tothe' yarn and after reaction with the acid radicle thereof, forms a salt, the crystals of which do'notinterfere as theyarn passes through said guides. The length of treatment that the materials receive in such solutions is preferably limited such 'that the materials are not saponified to any great extent. For instance, it is found preferable in mostcases to limit the first saponification or sensitization in time, temperature and concentration such that the yarns at those places treated lose only'about 2 to '7 per cent of their weight. Obviously; the concentration, temperature and duration of treatment of the yarns will vary according to the sensitizing agent employed to produce this li'rri ited degree of saponification. As this sensitizing of the yarns or fabric is preferably done during a winding operation the period of time of action and penetration is relatively short and the ternperature is about room temperature, the concentration should be such that the solution applied has a pH value of above 10.

After the yarns have been sensitized as above described, that is, to such an extent that they have lost between 3 and '7 per cent of their weight, the same may be formed into cloth or fabric by any suitable method. Cloth or fabric so formed may then be treated in a developing bath or given a second treatment to saponify the places of the yarns sensitized to any desired extent. The second or developing bath preferably consists of a basic solution having a pH value of between 8 to 10.5 and the duration and temperature of treatment so regulated that the unsensitized portions of the yarn, if any, are unafiected by the second treatment. The preferable method of carrying out this second step of saponification is to treat the fabric in a bath containing from 5 to 10 grams per litre or more of soap in an aqueous media at a temperature from 70 C. to boiling. The duration of treatment in the soap bath will depend upon the sensitization, the soap and the temperature of the bath and may vary between 10 minutes and one hour, depending upon the degree of saponiflcation desired. Although soap solutions are normally preferred for developing concentration, the time and temperature of the developing orcsecond:sapbriifyingzbathgttheysensiq tized parts omtheyama omfabricsjimam'heg caused to' lose as muchirasm tper centcoiemoreaofiithei-li app eat 'on the; tmsensitizediiportion of; rw E '50 sensitizedrya un t-her saporiificationsaflecting {01113751313118 ni-fle'd ot se'n'sitized places wlthisubstantially no saponificationi taking; place J'OIFltheJ unsaponi o e -yarn 'oiid'abric produceditherefromi k h ficati onor second saponificatiommay; be desired to obtaingreater depth in i sha'dezrthan where; only a light perlodic saponificatlon ihasebeenuapplied originally; or even ito' Jobtainvsuchian degree of sap'oniflca'tion that the 'saponifie'diplacesisubstam tially or completely resist:dyestufisowhichanore mally dye cellulose acetate :,and like yarns but which have no mantra-motion and the regeneratedl cellulose yarns. i' i'hisifurther sapcnifi'cation or development may bei effected byatreating the yarns "oitatues in hydrolyzing baths :of

moderate pH value such aalfor example;-9 or -10, which normally have substantially :no hydrolyzing', or very little and slow I hydrolyzing. 'actionron the yarns containing organic :esters of 1 cellulose. 'l'hese-baths may consist oflufor example; soap and water', sodium acetate"and: water; and; various buffered baths containing sodium, potassium or other similarly" reacting salts in the presence of buffering "substances or without the aid of such buffering substances. The: result of :the immension in such baths o ls to increase the saponification in the saponified onsensitized places with substantiallymo saponification: in thecunsaponifled or unsensitlzed places-and: rtheuresult :ofnthe reaction is more 'rapid when the temperature of the bath is elevated," for example,-* to 180? C. (up

to thboil; I? The: increase in saponification ,isiape precia-ble in"jsuch baths 'even ithin such times mg fope'r'atidn. Also;- the: subsequent 'saponification or the y'a'rn when treated in soap baths,-etc. maybe prevented'by washing'indilutaacids prior to entering the scouring bath containing- .the soapif By thus treating the yarn either by w'ashing orby a treatment inadi-luteacidthe"whole I of the 'yarrfis' brought to such a state that any saponification treatment applled thereto will not afiect the previously sensitized or 1 saponified 'portions more than 'tl ie unsensitized orunsaponified portions? As an aidto illustrating this invention slam as limitationathe following examples are given:

ema 1 f f An acetone solublebellulOse acetate yarn is placed in a humido'r having an atmosphere of relative humidity above 65per cent forv such a period of timefthatthe moisture regain oi the yarn amounts to about 4 per cent on the Weight of the yarn. The yarn is placed on the supply bobbin spindle of a re-Winding machine and wound at 100 meters per minute and caused to contact with a furnishing roller or other device applying a 20 per cent solution of sodium hydroxide to the yarn in such an amount that the yarn is saponified to a weight loss of 5 per cent when the yarn is washed in cold water to remove the sodium acetate formed and its weight loss determined. A quantity of this yarn not washed in cold water is treated in grams per litre soap solution at 99? C. for 30 minutes. It is found that the saponification has progressed to a weight loss of 10 per cent and the affinity for cotton colors correspondingly increased. It is found that the saponification of the yarn is uniform throughout its length and woven into a fabric and dyed shows substantially no unevenness due to irregularities in the depth or amount of saponification of the yarn.

Example I! Example I is repeated except that theyarn during the winding operation is caused to periodically contact with a furnishing device furnishing a sensitizing material containing a ZO'per cent solution of sodium hydroxide, instead of continuously sensitizing the yarn. The yarn dyed with a cotton dyestufi is found to have a sharp line between the part of the yarn having an affinity for the cotton dyestufi and the unsaponified part of the yarn. I'he yarn at the parts thereof that have been saponified are found to talce dyes having aifinity for cotton evenly, without streaks or variations in shade.

Example III I A fabric is formed from yarns containing an acetone soluble cellulose acetate, which fabric is rolled into package. The fabric is placed in a chamber having an atmosphere of relative humidity above 65 per cent for a period of time such that the moisture regain of the yarn s45 amounts to about 4 per cent on the weight of the yarn. The fabric is passed through a printing device that applies to the fabric in a pattern a paste containing a saponifying agent. The labr is then treated in a heated bath containing ii) grams per litre of soap for minutes. The pattern is found to be developed and takes dyes having aifinity for cotton.

While in the foregoing specification I have mH'rr uAuCLi various portions of the yarn a varying amount oi sensitizing material which results when developing the yarn in a soap bath in a yarn having iortions, each portio having a correspondingly icrent degree of poniication and afllnit for the various dyestuns. Further, there may be produced novel effects on the yarn or fabric in two Winding operations, the material having a diiierent moisture content in each winding opera'tion, thus varying the amount and type of sensitizing places on th iaterial.

The yarns prior to be treated in an atmosphere having a relat y high humidity may be lubricated. It is pro: red when employing a lu-- bricant for such yarns to employ one which is specific instances and examples, it is not y intention that the scope of the invention Numerous effects may be obtained on the torn or labrics produced therefrom by applying amass? non-saponifiable and one which permits a relatively fast regain of moisture content of the yarn when the same is placed in a humid atmosphere. An example of a preferred lubricant is a dispersion of sulphonated naphthene in mineral oil that may or may not contain an acid color as a tinting compound.

Having described my invention what I desire to secure by Letters Patent is:

1. Process for saponifying filaments, yarns, fabrics and other materials having a basis of ester of cellulose, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, and subsequently saponiiying the materials while they still possess a high moisture content.

2. Process for saponifying filaments, yarns, fabrics and other materials having a basis of organic ester of cellulose, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, and subsequently saponifying the materials while they still possess a high moisture content.

3. Process for saponifying filaments, yarns, fabrics and other materials having a basis of cellulose acetate, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, and subsequently saponifying the materials while they still possess a high moisture content.

4. Process ,for saponifying filaments, yarns, fabrics and other materials having a basis of cellulose acetate, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content substantially to its maximum value at the temperature of treatment, and subsequently saponifying the materials while still possess this moisture content.

5. A process of manufacturing artificial materials, which comprises subjecting yarns, filaments, fabrics and other materials having a basis of organic ester of cellulose to the action of a humid atmosphere whereby their moisture content is raised substantially, sensitizing to saponification at least part of the materials by treatment with a solution having a basic reaction, and then subjecting them to the action of an alkaline saponilying agent.

6. A process of manufacturing artificial mate rials, which comprises subjecting yarns having a basis of organic ester of cellulose to the action of a humid atmosphere whereby their moisture content is raised substantially, subjecting the yarns at intervals along their length to a preliminary saponification during a winding operation, and subsequently subjecting the yarns to further saponitiication with a substance of low alkalinity while they still contain reaction products derived. from the preliminary saponification.

'7. Process for locally saponifying filaments, yarns, fabrics and other materials having a basis -oi organic ester of cellulose, which comprises subjecting the materials to the action of a atmosphere to increase their moisture content, removing from selected areas of the material a small proportion of its acidyl content by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to sapcnification, and subsequently completing the desired saponification of the pretreated arcas by treating the material, while it still contains reaction products derived from the pretreatment, with an alkaline substance which less alkaline than that employed in the pretreatment and which has substantially no saponiiying Bill pretreated is rendered more sensitive to saponi-' action on the areas of the material which have not been pretreated.

8. Process for locally saponifying filaments, yarns, fabrics and other materials having a basis of cellulose acetate, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, removing from selected areasof the material a small proportion of its acidyl content by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and subsequently completing the desired saponiflcation of the pre treated areas .by treating the material, while it still contains reaction products derived from the pretreatment, with. an alkaline substance which is less alkaline than that employed in the pretreatment and which has substantially no sapon- I ifying action on the areas of the material which have not been pretreated.

9. Process for locally saponifying filaments, yarns, fabrics and other materials having a basis of organic ester of cellulose, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, removing from selected areas of the material a small proportion of its acidyl'content by pretreatment with a saponifying solution having a pH value of from 10 to 14, whereby the material wherever pretreated is rendered more sensitive to saponiflcation, and subsequently completing the desired saponification of the pretreatedareas by treating the material, while it still contains reaction products derived from the pretreatment, with a solution having a pH value of from 8 to 11 and which is less alkaline than that employed in the pretreatment and. which has substantially no saponifying action on the areas of the material which have not been pretreated.

10. Process for locally saponifying filaments, yarns, fabrics and other materials having a basis of cellulose acetate, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, removing from selected areas of the material a small proportion of its acidyl content by pretreatment with a saponifying solution having a pH value of from 10 to 14, whereby the material wherever flcation, and subsequently completing the desired saponification of the pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with a solution having a pH value of from 8 to 11 and which is less alkaline than that employedin the pretreatment and which has substantially no saponifying action on the areas of the material which have not been pretreated.

11. Process for locally saponifying artificial materials having a basis of. cellulose acetate, which comprises subjecting the materials to the action of a humid atmosphere to increase their moisture content, removing from selected areas of the material during a winding operation a small proportion of acidyl content by pretreatment with an alkaline saponifying agent, whereby the material wherever pretreated is rendered more sensitive to saponification, and subsequently completing the desired saponification of the pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with an alkaline substance which is less alkaline than that employed in the pretreatment and which has substantially no saponifying action on the areas of the material which have not been pretreated.

12. Process for locally saponifying artificial materials having a basis of cellulose acetate,

which comprises subjecting the materials to the completing the desired saponification of the pretreated areas by treating the material, while it still contains reaction products derived from the pretreatment, with an alkaline substance which is less alkaline than that employed in the pretreatment and which has substantially no saponifying action on the areas of the material which have not been pretreated. 

